LU-5674 test: print spl debug info

LU-5674 test: print spl debug info

Print /proc/spl files in case of tests fail

This patch is back-ported from the following one:
Lustre-commit: acdaca8426a4ca21dab6f6b39365befb3a8f5ffc
Lustre-change: http://review.whamcloud.com/11580

Signed-off-by: Minh Diep <minh.diep@intel.com>
Change-Id: Ia255347e2ad47732e6f86f9d8cd7bfa883bcde9b
Reviewed-on: http://review.whamcloud.com/12590
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Isaac Huang <he.huang@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>